1. Field of the invention
The invention relates to the field of doping a semiconductor substrate from a solid phase dopant source.
2. Prior art
As critical dimensions in semiconductor fabrication technology become smaller, it becomes necessary to form shallower doped regions such as source and drain regions in field-effect transistors. One technique for achieving shallower regions is to diffuse the dopant from a solid phase dopant source such as described in U.S. Pat. No. 5,518,945.
It is important to control the amount of dopant in the solid phase diffusion source and to provide a reliable, easy to fabricate source.
The chemistry used in the present invention employs organic esters such as triethylborate (TEB) as a source of dopant for the solid phase dopant source. These esters have been used as a source of p-type and n-type dopant to form for instance, boron and phosphorus doped glass layer which can be reflowed. Such glass layers are used as interlayer dielectrics.